Steven Mason has worked at the council for nearly 15 years and said he was leaving his role to pursue fresh challenges.

The change at the top comes after the Conservatives overtook Labour to become the biggest party on the council in the local elections on May 4.

Speaking about his departure, Mr Mason said: “It is with sadness that I have decided to leave the council after nearly 15 years service to the residents of Northumberland .

“During my time the council has faced many challenges, most notably local Government reorganisation and the impact of cuts in local Government funding over an extended period of time.

“The council’s approach and direction will change significantly following the recent county council election and it is an appropriate time for new managerial leadership at a time when the political leadership has changed with a radically different agenda.”

Mr Mason worked in a number of financial roles at the authority and has been chief executive for the past three years.

Prior to that he was the chief executive of the North Durham Healthcare Trust and he led the transfer of health services into Durham’s £97m University Hospital.